Boxster/Boxster S coolant system differences?
 

I am planning on adding the S center radiator to my 99 Boxster base. Should I also consider replacing the coolant hoses pipes with S hardware? I seem to remember reading the S pipe diameter was larger than the base so I am assuming if I wanted to do this conversion I would have to replace inlet/outlet coolant connections to the engine? I have reviewed the center radiator install on Pedro's Board and Pelican but no discussion regarding coolant lines.

Any thoughts?

Others will chime in too, but in my opinion, no, you do not need to change the coolant tubes. Any additional cooling capacity for the S was engineered as the result of the larger displacement engine. Since you have not changed the displacement of your engine, the factory engineering should be sufficent for your engine. The third radiator is just added peace of mind for warmer climates or prolonged idleing (like stuck in traffic day after day.)

Now when you go to upgrade your engine, then maybe....

The hard pipes at the front of the car are a different diameter on the S compared to the base model. What this means is that the new "T" pipes that are used to plumb in the center radiator are too large for the pipes on the Base.

Pelican have a DIY where they use standard brass plumbing as a reducer to allow the correct size rubber hose to attach to the hard pipe, but I have seen first hand this fail at the track (after 2 years of being installed) causing coolant to spill out, annoying all his mates at the track and ending his day early. I don't recommend this method.

I personally just tightened the heck out of the hose clamps using the standard pipes, and have had no issues after 2000 track miles.

There used to be someone who welded the S ends on the base hard pipes to make the best solution, but the name escapes me. This would be the best solution, but additional cost. EDIT - It's precision chassis works.

http://www.precisionchassisworks.com/boxster-cooling-line-modification.html

Hope this helps.

PS. if you are not tracking the car, there really is no need for the center radiator. If you are overheating in normal traffic, there is another fault you would be better tracking down than trying to mask the problem by fitting the center radiator.

I have some experience on this as I did this between January through March this year. The pipe off the 3.2 motor fit the hoses from the 2.7 motor I replace both of those hose with the same parts and clamps. I bought the OEM tee hoses, center radiator and frame from the dealer. The tee hose is larger by about 1/8". When I removed the original hose from the left and right side radiator I slipped on 2 new spring clamps on the end that clamps the original plumbing. I was able to loosen and slide the hose and connector from under the chasis enough to get 2 clamps on the new slightly larger Tee hose. The connector pipe has 2 ribs One clamp before the first rib one clamp between the ribs. No drip no dribble in 6200 miles and 15 track days.

So how difficult would it be to swap out the 99 base boxster coolant lines for boxster S coolant lines?

Finally completed this project. I had Precision weld the adapters onto my existing pipes and installed the radiator and "S" Y hoses to the new radiator. Very easy to do and works great.

The bumper on my base model needed repair and painting and since qualityporscheparts is local for me, I obtained an S bumper simply because I like the styling.

I first mounted the newly-painted bumper with nothing behind it, but this looks like it makes an air conditioning metal line vulnerable to damage, so I then installed an S radiatior plus rubber duct also from qualityporscheparts. I have no intention of plumbing this into my cooling system as I'm certain I don't need it nor do I think it would improve anything. I'll admit I've likely degraded my car's aero slipperiness.